Sucrose flotation for Larvae

I want to clean larval stages from debris and bacteria in my liquid culture.
I have trouble to clean Larval stages (eg. L2) with sucrose flotation. Does the protocol only work for Adults?
[ I mix my worms in M9 1:1 with 60% sucrose, overlay with M9 or 0,1M NaCl and spin for 5 minutes.]
Thanks for help,